The present application relates to an image signal processor, an image signal processing method for use in the same, and a program, and more particularly to an image signal processor, an image signal processing method for use in the same, and a program which are suitable for being used when an xvYCC signal is generated based on a photograph film of a movie.
Hereinafter, an image signal which can be treated by an image display apparatus typified by a television receiver has been signals of the three primary colors of red, green and blue (hereinafter referred to as “RGB signals”), or a component signal which is obtained through conversion based on the RGB signals and which is composed of a luminance signal and a chroma (color difference) signal (hereinafter referred as “a Y′PbPr signal”).
Thus, the primary color point which is decided based on a chromaticity point of a cathode ray tube (CRT) which has been adopted in the image display apparatus for a very long time is used in the RGB signals treated in the related art image display apparatus. In other words, the RGB signals are standardized on the premise of being displayed on the CRT. Therefore, a color space capable of being expressed by the RGB signals is enough as long as it can cover a color reproduction range.
However, in recent years, a plasma display device, a liquid crystal display device and the like each of which has a color reproduction range wider than each of a color reproduction range of the CRT, and a color space capable of being expressed by the RGB signals or the component signal have appeared as an alternative of the CRT. When the related art ROB signals or component signal is inputted to the plasma display device or liquid crystal display device having such a wide color reproduction range, the color reproduction range of the plasma display device or the liquid crystal display device can not be sufficiently utilized.
In order to cope with the problem described above, the applicant of this patent application has already proposed an image signal capable of expressing the color space wider than that which the RGB signals or the component signal can express. This technique, for example, is disclosed in Japanese Patent Laid-Open No. 2006-33575. Also, this image signal is enacted as a new extended color space international standard, xvYCC, for motion picture (IEC 61966-2-4). Hereinafter, the image signal complying with this international standard will be referred to as an xvYCC signal.
Along with the standardization of the xvYCC signal, the wide color gamut promotion for the image has been advanced so that the plasma display device, the liquid crystal display device and the like can respond to the xvYCC signal. Actually, television receivers advocating that they respond to the xvYCC signal begin to come into wide use (hereinafter referred to as “x.v.Color-compliant television receivers”).
As has been described so far, the side color gamut promotion on the hardware side typified by the appearance of the x.v.Color-compliant television receiver has been advanced. However, paying attention to a software side, that is, the image signal, although the xvYCC signal is standardized, actually, the number of video contents each using the xvYCC signal is still very small.
Thus, in order to increase the number of video contents each using the xvYCC signal, a movie film as a material thereof is being watched. The color reproduction range of the movie film is wide to exceed that of each of the related art RGB signals and component signal, and is narrower than that of the xvYCC signal. Therefore, it is expected that the xvYCC signal is generated based on the movie film without compressing the color reproduction range which the movie film originally has.
Note that, in the related art as well, there exists a technique for converting the ROB signals or the like into predetermined ones based on the movie film. However, with the related art concerned, the conversion is carried out so as to further narrow the color reproduction range. As a result, the color space which the movie film originally has can not be sufficiently reproduced with the RGB signals obtained after completion of the conversion.